Displaying 20 results from an estimated 9000 matches similar to: "recommended computing server for R (March 2009)?"
2004 Sep 28
3
slow loops in Monte Carlo Simulations
Hi there,
I am running Monte Carlo Simulations in R using ordinary "while
(condition)" loops. Since the number of iterations is something like
100.000 and within each iteration a given subsample is extended
sequentially it takes hours to run the simulation.
Does anyone know if there is either a way to avoid using loops in
Monte Carlo Simulations or how to include possible faster
2005 Sep 23
4
books about MCMC to use MCMC R packages?
Dear list users,
I need to learn about MCMC methods, and since there are several packages in
R that deal with this subject, I want to use them.
I want to buy a book (or more than one, if necessary) that satisfies the
following requirements:
- it teaches well MCMC methods;
- it is easy to implement numerically the ideas of the book, and notation
and concepts are similar to the corresponding R
2009 Jan 30
5
[LLVMdev] Performance vs other VMs
The release of a new code generator in Mono 2.2 prompted me to benchmark the
performance of various VMs using the SciMark2 benchmark on an 8x 2.1GHz
64-bit Opteron and I have published the results here:
http://flyingfrogblog.blogspot.com/2009/01/mono-22.html
The LLVM results were generated using llvm-gcc 4.2.1 on the C version of
SciMark2 with the following command-line options:
llvm-gcc
2018 Sep 19
4
Bias in R's random integers?
On Wed, 19 Sep 2018 at 13:43, Duncan Murdoch <murdoch.duncan at gmail.com>
wrote:
>
> I think the analyses are correct, but I doubt if a change to the default
> is likely to be accepted as it would make it more difficult to reproduce
> older results.
I'm a bit alarmed by the logic here. Unbiased sampling seems basic for a
statistical language. As a consumer of R I'd
2009 Jan 08
2
VaR-Monte carlo Simulation, Historic simulation, Variance-Covariance Simulation
Dear R helpers
Suppose I have a portfolio of securities with exposure to Equity, Bonds and Forex (say $ 1000000 each).
Is there any fucntion in R that will help me calculate Value at Risk (VaR) using Monte carlo Simulation , Historic simulation and Variance - Covariance Simulation.
With regards
Maithili
2012 Nov 23
1
Spatstat: Mark correlation function
I normally use the following code to create a figure displaying the mark
correlation function for the point pattern process "A":
M<-markcorr(A)
plot(M)
I have now started to use the following code to perform 1000 Monte Carlo
simulations of Complete Spatial Randomness (CSR). It is a Monte Carlo test
based on envelopes of the Mark correlation function obtained from simulated
point
2011 Oct 17
1
using mean substitution
Hi, all,
I'm running a monte carlo simulation with missing data. The data are arranged such that there are k columns and n rows over a set number of simulations (set to 10 right now so it runs fast while I set everything up). The data are integers, numbers 1-7 only (normal distribution). The simulations are set up and run without a hitch, including imposing NA missing values at a specified
2012 May 30
3
alternative generator for normal distributed variables
Hello,
currently I'm working on a model based on Monte-Carlo-Simulations.
I observed that a generated normal distributed times series using
rnorm(100,mean=0,sd=1)
is far away from being not autocorrelated.
Is there any other gerenator implemented in R, which might solve my problem?
--
View this message in context:
2002 May 30
3
Building a stand-alone package
Dear R users,
I'm working with Windows 2000 and R -- note that I could maybe work with Linux too...
I would like to know if it is possible to build a stand-alone statistical
package which:
-- could be programmed in R language,
-- could have a nice graphical interface with buttons and menus (this package
will be distributed to non-statistician people),
-- could realize statistical operations,
2005 Aug 13
2
monte carlo simulations/lmer
Hi - I am doing some monte carlo simulations comparing bayesian (using
Plummer's jags) and maximum likelihood (using lmer from package lme4
by Bates et al).
I would like to know if there is a way I can flag nonconvergence and
exceptions. Currently the simulations just stop and the output reads
things like:
Error in optim(.Call("lmer_coef", x, 2, PACKAGE = "Matrix"), fn,
2005 Nov 08
1
Hybrid Monte Carlo algorithm (MCMC)
Hi all,
I'm trying to estimate a nested model (purchase decision, cloglog formula, &
quantity bought given a purchase, truncated Poisson). Some of the parameters
are mixed (6) and 4 are fixed for all the respondent.
The simulated ML (500 simulations) method forwards highly correlated
estimates.
After some research, Hybrid Monte Carlo seems to be a good alternative to
estimate the model. I
2005 Mar 09
2
Question about biasing in sd()???
Hi,
Can anyone help me with the following. I have been using R for Monte
Carlo simulations and got some results I couldn't explain. Therefor I
performed following short test:
--------------
mean.sds <- NULL
sample.sizes <- 3:30
for(N in sample.sizes){
dum <- NULL
for(I in 1:5000){
x <- rnorm(N,0,1)
dum <- c(dum,sd(x))
}
mean.sds<- c(mean.sds,mean(dum))
}
2009 Mar 26
1
pgmm (Blundell-Bond) sample needed
Dear R Experts---
Sorry for all the questions yesterday and today. I am trying to use Yves
Croissant's pgmm function in the plm package with Blundell-Bond moments. I
have read the Blundell-Bond paper, and want to run the simplest model
first, d[i,t] = a*d[i,t-1] + fixed[i] + u[i,t] . no third conditioning
variables yet. the full set of moment conditions recommended for
system-GMM,
2008 Apr 11
2
Questions related to plotting boxplots of time series data
List,
I have looked through several R books and searched the web to find
answers to my questions with no results. I have a ensembles of time
series data (essentially from Monte Carlo simulations) which I would
like to summarize as a time series of boxplots. I don't know how to do
this and I am not sure how I should structure the data to get what I
want. Another related question: while
2008 Nov 16
3
chisq.test with simulate.p.value=TRUE (PR#13292)
Full_Name: Reginaldo Constantino
Version: 2.8.0
OS: Ubuntu Hardy (32 bit, kernel 2.6.24)
Submission from: (NULL) (189.61.88.2)
For many tables, chisq.test with simulate.p.value=TRUE gives a p value that is
obviously incorrect and inversely proportional to the number of replicates:
> data(HairEyeColor)
> x <- margin.table(HairEyeColor, c(1, 2))
>
2010 May 24
2
adding one line to a plot
Hello!
I am running a very simple mini Monte-Carlo below using the function
tstatistic (right below this sentence):
tstatistic = function(x,y){
m=length(x)
n=length(y)
sp=sqrt( ((m-1)*sd(x)^2 + (n-1)*sd(y)^2)/(m+n-2) )
t=(mean(x)-mean(y))/(sp*sqrt(1/m+1/n))
return(t)
}
alpha=.1; m=10; n=10 # sets alpha, m, n - for run 1
N=10000 # sets the number of simulations
n.reject=0 # counter of num.
2016 Sep 26
2
Publication & Project: Verificarlo: checking floating point accuracy through Monte Carlo Arithmetic
Hi,
We have recently published a paper on floating point accuracy analysis
through Monte Carlo Arithmetic. We also released the open-source tool
Verificarlo (https://github.com/verificarlo/verificarlo) that relies on
LLVM for instrumenting floating point operations.
Could you please add our paper to http://llvm.org/pubs/ ?
Verificarlo: checking floating point accuracy through Monte Carlo
2009 May 05
1
big databases
Dear all,
I have a .dta database which is about 400 MB. I cannot open it though I have
no problem to import smaller ones (80 MB or even 174 MB).
I tried to modify some options with --max-mem-size=2047M --max-vsize=2047M.
But it does not seem to be enough.
I do not know the exact meaning of these options : vsize seems to be made
for vectors.
I have got Monte Carlo simulations running in another
2008 Feb 04
2
maybe a bug in the system.time() function? (PR#10696)
Full_Name: Alessandra Iacobucci
Version: 2.5.1
OS: Mac OS X 10.4.11
Submission from: (NULL) (193.48.71.92)
Hi,
I am making some intensive simulations for the testing of a Population Monte
Carlo algorithm. This involves also a study of the CPU times in two different
case.
What I am trying to measure is the "real" CPU time, the one which is independent
on the %CPU.
I'm using the
2002 Aug 02
1
Means of Monte Carlo simulated lists
Hello,
I am doing simulations, and I generate a list at each iteration (with
three component matrices in the example below), saving the results in
a list. For example, after two iterations, I have something like
> str(sim.theta)
List of 2
$ :List of 3
..$ : num [1:6, 1:4] -3.67 -1.07 -2.99 -18.38 -3.26 ...
..$ : num [1:6, 1:6] -7.56 -3.14 -4.99 1.03 2.79 ...
..$ : num [1:6, 1:4]